EntityHome update not working as expected!

[loop0]

Hi, if I chose a Department object from my suggestionbox all other fields gets filled and the update button appears, but if I click on the update button the Entity doesn't get updated in database and the update buttons dissapears (as the entity is not managed).

How can I make this thing works?

My departmentHome.xhtml:

<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
    xmlns:s="http://jboss.com/products/seam/taglib"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:rich="http://richfaces.org/rich"
    xmlns:a4j="http://richfaces.org/a4j"
    template="layout/template.xhtml">
   
<ui:define name="body">
<h1>Department</h1>
     <a4j:region renderRegionOnly="true">
     <h:form id="departmentHomeId" styleClass="edit">
          <rich:panel>
               <f:facet name="header">Department edit</f:facet>
               <s:decorate id="departmentName" template="layout/edit.xhtml">
                <ui:define name="label">Name:</ui:define>
                <h:inputText id="departmentNameInput"
                               size="50"
                              value="#{departmentHome.instance.name}"
                           required="true"/>
            </s:decorate>
            <rich:suggestionbox for="departmentNameInput"
                   suggestionAction="#{departmentHome.getDepartmentHints}"
                                 var="dep"
                            minChars="3">
                     <h:column>
                                <h:outputText value="#{dep.name}"/>
                         </h:column>
                          <a4j:support ajaxSingle="true" event="onselect" reRender="departmentHomeId">
                            <f:setPropertyActionListener value="#{dep.id}" target="#{departmentHome.id}" />
                        </a4j:support>
            </rich:suggestionbox>
            
            <s:decorate id="departmentAcronym" template="layout/edit.xhtml">
                <ui:define name="label">Acronym:</ui:define>
                <h:inputText id="departmentAcronymInput"
                               size="50"
                              value="#{departmentHome.instance.acronym}"
                           required="true"/>
            </s:decorate>
        <div style="clear:both">
                <span class="required">*</span> Required fields
        </div>
          </rich:panel>
          
          <div class="actionButtons">

            <h:commandButton id="update"
                          value="Update"
                         action="#{departmentHome.update}"
                       rendered="#{departmentHome.managed}"/>
          </div>
     </h:form>
     </a4j:region>
   
   
</ui:define>
</ui:composition>